At present, door closers are ordinarily adopted in safety doors, anti-theft doors, room doors, toilet doors, kitchen doors, screen window doors, cabinet doors or windows and the like for realizing the automatic closing function, thereby realizing effective fireproof and anti-theft effect. In the prior art, the types of the door closers can be mechanical type, pneumatic type and hydraulic type generally, wherein the mechanical door closers generally adopt springs for constituting elastic components, when an operator pushes a door leaf, the spring is driven to accumulate energy by stretching, compression or torsion and other deformation, when the operator leaves the door leaf, the status of the spring is changed from energy accumulation to energy release, and a pull rod can close a door under the drive of the spring. But, the mechanical door closers in the prior art have one problem during the using process, that is the door closer can only fix a position of the door leaf when the opening angle of the door leaf exceeds 90 degrees, otherwise, the door closer can automatically drive the door leaf to close, so that the use is not convenient enough sometimes.